Network Analysis

Computations on networks comprise a different set of analytical functions in GISs. Here, the network may consist of roads, public transport routes, high-voltage power lines, or other forms of transportation infrastructure. Analysis of networks may entail shortest path computations (in terms of distance or travel time) between two points in a network for routing purposes. Other forms are to find all points reachable within a given distance or duration from a start point for allocation purposes, or determination of the capacity of the network for transportation between an indicated source location and sink location. 

Network analysis can be performed on either raster or vector data layers, but they are more commonly done on the latter, as line features can be associated with a network and hence can be assigned typical transportation characteristics, such as capacity and cost per unit. 

Various classical spatial analysis functions for networks are supported by GIS software packages. The most important network analysis functions are:

• Optimal Path Finding, which generates a least-cost path on a network between a pair of predefined locations using both geometric and attribute data.
• Network Partitioning, which assigns network elements (nodes or line segments) to different locations using predefined criteria.